Preparation method and application of a flexible self-supporting silicon/carbon nanotube film composite electrode

Abstract

The invention belongs to the technical field of lithium ion batteries, and discloses a preparation method and application of a flexible self-supporting silicon / carbon nanotube film composite electrode. The invention utilizes a floating catalytic chemical vapor deposition method to prepare a continuous carbon nanotube film. The modified silicon powder floats on the water surface, and the cylindrical carbon nanotube continuum is collected through the water by rolling the roller. In this state, the carbon nanotube continuum has a large surface area, its own adsorption and the cylindrical carbon nanotube continuum. The volume of the body shrinks sharply when it encounters water. The silicon powder floating on the water surface is evenly and tightly wrapped in it. film, and finally rolled to obtain a flexible silicon-carbon nanotube composite electrode film material. Compared with the prior art, this method has a higher silicon load, and the silicon is more uniformly distributed in the carbon tube film, which is beneficial to the improvement of the specific capacity and cycle performance of the assembled lithium-silicon battery.

Description

Technical field [0001] The present invention relates to a class of silicon carbon anode materials, mainly relates to a class of silicon and carbon nanotube composite materials, and its application as a lithium-ion battery anode material, belongs to the field of lithium-ion battery technology. Background [0002] In the existing secondary battery system, whether from the development space, or from the technical indicators such as life, specific energy, working voltage and self-discharge rate, lithium-ion batteries are the most competitive secondary batteries at present. With the continuous development of electronic technology, higher requirements are also put forward for lithium-ion batteries, which require higher energy density, better cycle life, better high and low temperature charging and discharging performance and safety performance, which requires lithium-ion batteries with positive and negative electrode materials need to be further developed and improved. [0003] At pres...

AI Technical Summary

Problems solved by technology

However, the existing silicon-carbon composite electrodes and lithium-silicon batteries still have some shortcomings, such as being limited to the use of traditional copper foil as a current collector, the combination of active materials and copper foil is not tight enough, easy to fall off, and cannot achieve flexibility; The active material needs to be prepared into a slurry before it can be combined with the current collector, and the steps are cumbersome

And in the existing silicon-carbon nanotube composite technology, one type is to composite the carbon nanotube powder with silicon powder and then press the composite powder to form a film by suction and filtration. The flexible film obtained by this method has a loose structure and is resistant to bending. Poor foldability, and it is not easy to realize the preparation of large-area composite membranes; the other is to combine ready-made carbon nanotube membranes with silicon, and the infiltration method and coating method are mostly used. The silicon loading capacity of the composite membrane obtained by this method is low, Moreover, silicon is not uniformly dispersed in the carbon nanotube film, and most of the silicon is only loaded on the surface of the carbon nanotube film.

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